#include<bits/stdc++.h>
using namespace std;
int a,b,c,d,e,i,j,ii,jj,zx,xc,t,tes,f[200009],boo,pi,k[200009],qi,qqi,bo[200009],fx[200009];
pair <int, int> p[3000009],q[200009],qq[200009];
void swp(int q, int w){
swap(f[q],f[w]);
swap(f[a-q+1],f[a-w+1]);
}
int main(){
//ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
//cin>>tes;
scanf("%d\n",&tes);
for(t=1; t<=tes; t++){
//cin>>a;
if(t!=tes) scanf("%d\n",&a); else scanf("%d",&a);
for(i=1; i<=a; i++){
//cin>>f[i];
if(i==a) scanf("%d",&f[i]); else scanf("%d ",&f[i]);
}
boo=0;
for(i=1; i<=a/2; i++){
if(f[i]>a/2){
boo=1;
break;
}
}
if(boo==0){
/*boo=0;
for(i=1; i<=a/2; i++){
if(f[a-i+1]-f[i]!=a/2){
boo=1;
break;
}
}
if(boo==1){
cout<<-1<<endl;
continue;
}*/
pi=0;
for(i=1; i<=a/2; i++){
k[f[i]]=i;
}
for(i=1; i<=a/2; i++){
if(k[i]==i) continue;
pi++;
p[pi].first=k[i];
p[pi].second=i;
c=k[i];d=i;
swap(k[i],k[f[i]]);
swap(f[c],f[d]);
}
for(i=1; i<=pi; i++){
swap(f[a-p[i].first+1],f[a-p[i].second+1]);
}
boo=0;
for(i=2; i<=a; i++){
if(f[i]<f[i-1]){
boo=1;
break;
}
}
if(boo==1){
// cout<<-1<<endl;
printf("-1\n");
continue;
}
//cout<<pi<<" "<<pi<<endl;
printf("%d %d\n",pi,pi);
for(i=1; i<=pi; i++){
//cout<<p[i].first<<" "<<p[i].second<<endl;
printf("%d %d\n",p[i].first,p[i].second);
}
continue;
}
boo=0;
for(i=1; i<=a/2; i++){
j=a-i+1;
if(f[i]+f[j]!=a+1){
boo=1;
break;
}
}
if(boo==0){
//printf("%d 0\n",a);
}else{
printf("-1\n");
continue;
}
qi=0;qqi=0;
for(i=1; i<=a/2; i++){
if(f[i]>f[a-i+1]){
qi++;
q[qi].first=a-i+1;
q[qi].second=i;
}else{
/*qqi++;
qq[qqi].first=a-i+1;
qq[qqi].second=i;*/
}
}
if(qi%2==1){
printf("-1\n");
continue;
}else{
//printf("%d 0\n",a);
}
if(1==1){
//just solution
for(i=1; i<qi; i+=2){
//cout<<q[i].first<<" l "<<q[i+1].second<<endl;
pi++;
p[pi].first=q[i].first;
p[pi].second=q[i+1].second;
swp(q[i].first,q[i+1].second);
}
/*for(i=1; i<=a; i++) cout<<f[i]<<" rt ";
cout<<endl;*/
boo=0;
if(boo==0){
/*boo=0;
for(i=1; i<=a/2; i++){
if(f[a-i+1]-f[i]!=a/2){
boo=1;
break;
}
}
if(boo==1){
cout<<-1<<endl;
continue;
}*/
for(i=1; i<=a/2; i++){
k[f[i]]=i;
}
for(i=1; i<=a/2; i++){
if(k[i]==i) continue;
pi++;
p[pi].first=k[i];
p[pi].second=i;
c=k[i];d=i;
swap(k[i],k[f[i]]);
swap(f[c],f[d]);
}
/*for(i=1; i<=pi; i++){
swap(f[a-p[i].first+1],f[a-p[i].second+1]);
}
boo=0;
for(i=2; i<=a; i++){
if(f[i]<f[i-1]){
boo=1;
break;
}
}*/
if(boo==1){
// cout<<-1<<endl;
printf("-1\n");
continue;
}
//cout<<pi<<" "<<pi<<endl;
printf("%d %d\n",pi,pi);
for(i=1; i<=pi; i++){
//cout<<p[i].first<<" "<<p[i].second<<endl;
printf("%d %d\n",p[i].first,p[i].second);
}
continue;
}
}
}
return 0;
}
Compilation message
cat.cpp: In function 'int main()':
cat.cpp:12:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
12 | scanf("%d\n",&tes);
| ~~~~~^~~~~~~~~~~~~
cat.cpp:15:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
15 | if(t!=tes) scanf("%d\n",&a); else scanf("%d",&a);
| ~~~~~^~~~~~~~~~~
cat.cpp:15:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
15 | if(t!=tes) scanf("%d\n",&a); else scanf("%d",&a);
| ~~~~~^~~~~~~~~
cat.cpp:18:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
18 | if(i==a) scanf("%d",&f[i]); else scanf("%d ",&f[i]);
| ~~~~~^~~~~~~~~~~~
cat.cpp:18:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
18 | if(i==a) scanf("%d",&f[i]); else scanf("%d ",&f[i]);
| ~~~~~^~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
21 ms |
748 KB |
Integer parameter [name=x] equals to 9, violates the range [1, 8] |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
31 ms |
620 KB |
Output is correct |
| 2 |
Correct |
28 ms |
620 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
21 ms |
748 KB |
Integer parameter [name=x] equals to 9, violates the range [1, 8] |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
31 ms |
620 KB |
Output is correct |
| 2 |
Correct |
28 ms |
620 KB |
Output is correct |
| 3 |
Correct |
612 ms |
13036 KB |
Output is correct |
| 4 |
Correct |
578 ms |
11756 KB |
Output is correct |
| 5 |
Correct |
621 ms |
14768 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
21 ms |
748 KB |
Integer parameter [name=x] equals to 9, violates the range [1, 8] |
